From 38bd34b01fb4b1c5dab7aa2d9cd1fa6dfbc32625 Mon Sep 17 00:00:00 2001
From: Hermet Park <hermet@lottiefiles.com>
Date: Mon, 13 May 2024 12:22:55 +0900
Subject: [PATCH] animation/lottie: improved the precision of frame values.

Refined the logic for updating frame numbers
to ensure greater accuracy in value precision.

issue: https://github.com/thorvg/thorvg/issues/2266
---
 inc/thorvg.h                           |  1 +
 src/bindings/capi/thorvg_capi.h        |  1 +
 src/loaders/lottie/tvgLottieLoader.cpp | 16 +++++++++-------
 3 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/inc/thorvg.h b/inc/thorvg.h
index 5b152810..d56c8ada 100644
--- a/inc/thorvg.h
+++ b/inc/thorvg.h
@@ -1805,6 +1805,7 @@ public:
      *
      * @note For efficiency, ThorVG ignores updates to the new frame value if the difference from the current frame value
      *       is less than 0.001. In such cases, it returns @c Result::InsufficientCondition.
+     *       Values less than 0.001 may be disregarded and may not be accurately retained by the Animation.
      *
      * @see totalFrame()
      *
diff --git a/src/bindings/capi/thorvg_capi.h b/src/bindings/capi/thorvg_capi.h
index 52dd5518..da740f06 100644
--- a/src/bindings/capi/thorvg_capi.h
+++ b/src/bindings/capi/thorvg_capi.h
@@ -2254,6 +2254,7 @@ TVG_API Tvg_Animation* tvg_animation_new();
 *
 * \note For efficiency, ThorVG ignores updates to the new frame value if the difference from the current frame value
 *       is less than 0.001. In such cases, it returns @c Result::InsufficientCondition.
+*       Values less than 0.001 may be disregarded and may not be accurately retained by the Animation.
 * \see tvg_animation_get_total_frame()
 *
 * \since 0.13
diff --git a/src/loaders/lottie/tvgLottieLoader.cpp b/src/loaders/lottie/tvgLottieLoader.cpp
index 01057f42..5bd8fca1 100644
--- a/src/loaders/lottie/tvgLottieLoader.cpp
+++ b/src/loaders/lottie/tvgLottieLoader.cpp
@@ -313,17 +313,19 @@ bool LottieLoader::override(const char* slot)
 
 bool LottieLoader::frame(float no)
 {
+    auto frameNo = no + startFrame();
+
+    //This ensures that the target frame number is reached.
+    frameNo *= 10000.0f;
+    frameNo = roundf(frameNo);
+    frameNo *= 0.0001f;
+
     //Skip update if frame diff is too small.
-    if (fabsf(this->frameNo - no) < 0.0009f) return false;
+    if (fabsf(this->frameNo - frameNo) <= 0.0009f) return false;
 
     this->done();
 
-    //This ensures that the perfect last frame is reached.
-    no *= 1000.0f;
-    no = roundf(no);
-    no *= 0.001f;
-
-    this->frameNo = no + startFrame();
+    this->frameNo = frameNo;
 
     TaskScheduler::request(this);